1. Parasitic plant found in Nicobar eco hotspot
Septemeranthus partially depends on its host but also has leaves capable of photosynthesis
A new genus of a parasitic flowering plant has recently been discovered from the Nicobar group of islands. The genus Septemeranthus grows on the plant species Horsfieldia glabra (Blume) Warb. The parasitic flowering plants have a modified root structure spread on the stem of the tree and are anchored inside the bark of the host tree.
The plant was found on the periphery of the tropical forest in one of the biodiversity hotspots referred to as the Nicobar group of islands separated from the Andaman group of Islands by a wide gap of 160 km with heavy tidal flows.
The genus Septemeranthus has a distinct vegetative morphology, inflorescence architecture and floral characters. The leaves of the plant are heart-shaped with a very long tip and the ovary, fruit and seeds are ‘urceolate’ (earthen pot-shaped). The flowers have five persistent bracts having conspicuous margins. The name Septemeranthus is derived from the Latin word ‘septem’ meaning ‘seven’, referring to the arrangement of flowers. The details of the discovery were published in the Journal of Botanical Taxonomy and Geobotany Feddes Repertorium. The genus belongs to the family Loranthaceae, a hemi-parasite under the sandalwood order Santalales and is of widespread importance. Plants which are hemi-parasites are partially dependent on their host plants for nutrition. For instance, the newly discovered plant that derives nutrients from its hosts has green leaves capable of photosynthesis.
Loranthaceae is currently represented by nine genera and are found all across the country. What makes the new genus unique is that it is endemic only to the Nicobar group of islands. Lal Ji Singh, Joint Director, Botanical Survey of India, who has discovered the genus, said, “ During field studies, I found the birds consume viscous seeds of this new genus and seeds have potential of pseudo viviparous germination that deposit on the leaves and branches of their same plant which is already attached to host plants. After germination, the life cycle of the genus starts all over again.”
Hemi-parasites include are commonly referred to as mistletoes that contain 18 families, 160 genera and over 2,200 species. They need a host tree or shrub in order to thrive and exhibit a worldwide distribution in tropical as well as temperate habitats that evolved approximately five times in the order and are important in forest ecology, pathology and medicine. They play an important role as they provide food for frugivorous birds. In addition to Septemeranthus, four other genera on non-parasitic plants, Nicobariodendron (Hippocrateaceae), Pseudodiplospora (Rubiaceae), Pubistylis (Rubiaceae), Sphyranthera , (Euphorbiaceae) have also been discovered earlier from Nicobar group of islands, highlighting the ecological significance of the region. Recently a new species in the hemiparasitic family Loranthaceae, Dendrophthoe laljii have also been discovered from the Nicobar group of islands.
2. Faster spread of Omicron is not due to higher viral load
Omicron has replaced the Delta variant, which was considered highly transmissible, in almost every country across the world
The Omicron variant became the dominant variant infecting both vaccinated and the unvaccinated persons in many countries just one month after the World Health Organization designated it a variant of concern on November 26, 2021. Two months since, Omicron has become the dominant variant in every country that is witnessing a new wave. In short, Omicron has replaced the Delta variant, which was considered highly transmissive in almost every country across the world.
One of the defining features of a new variant is the higher transmissibility than the existing variant. If the Delta variant was found to be highly transmissible when compared with the Alpha variant, the Omicron variant has been found to be extremely transmissive when compared with the Delta variant.
Earlier studies suggested that the extremely high transmissibility of the Omicron variant was probably due to higher viral load in an infected person. The higher the viral load in a person, the greater are the chances that the infected person can successfully spread it to others. This is because the infected person tends to release larger amounts of the virus. While the Delta variant require a relatively longer period of exposure before a person gets infected, the Omicron variant has been found to spread within a few minutes of exposure.
But the results of a study posted in medRxiv preprint server (and is yet to be peer-reviewed) has found that the viral load is nearly the same with both variants — Delta and Omicron.
Backed by mutations
With the Omicron variant possessing many mutations that allows it to escape the immune system better even in previously infected or fully vaccinated people, the extremely high rate at which the Omicron variant is spreading might be due to inherent immune escape capabilities rather than the high viral load as it was previously thought.
A team led by researchers from the Harvard T. H. Chan School of Public Health in Boston, Massachusetts, obtained longitudinal, quantitative RT-PCR test results of swabs taken from the nose and throat of over 10,300 players from the National Basketball Association, the organisation responsible for professional basketball in North America. The period of study was restricted between July 5, 2021 and January 10, this year. From the beginning of the pandemic the players and other people associated with the Association have been undergoing regular testing. The league conducts frequent COVID-19 testing of its players and personnel.
The researchers used RT-PCR cycle threshold (Ct) values of less than 30 as a proxy for viral load. The PCR test amplifies the genetic material from coronavirus through multiple cycles. Since the coronavirus has RNA, it is first converted into DNA, and each cycle of amplification doubles the amount of DNA.
If there is just one DNA molecule to start with, the amount of DNA after 30 cycles of amplification will be one billion molecules. If there is more genetic material to begin with then fewer cycles of amplification would be sufficient to detect the DNA.
While the researchers were expecting that people infected with the Omicron variant would show higher viral load, the results were the just opposite. “The peak viral RNA based on Ct values was lower for Omicron infections than for Delta infections,” they write. For Omicron, the Cycle threshold (Ct) was 23.3, while for Delta the cycle threshold was 20.5. “These results suggest that Omicron’s infectiousness may not be explained by higher viral load measured in the nose and mouth by RT-PCR,” they write.
The clearance phase was also shorter for Omicron infections — 5.35 days — while for Delta it was 6.23 days.
Omicron and Delta
Another team led by researchers from the University of Geneva, Switzerland, went a step further to measure the number of infectious virus particles present on the swabs collected from 150 infected people. The results are posted on preprint server medRxiv, and the paper is yet to be peer-reviewed. They found that breakthrough infections caused by the Delta variant had lower number of virus particles than unvaccinated people with Delta infection. Surprisingly, the number of virus particles in vaccinated individuals with Omicron infection was comparable with individuals with Delta breakthrough infections.
Contrary to the previous notion that people infected with Omicron have higher viral loads than those infected with the Delta variant, the study by the University of Geneva found that vaccinated people infected with Delta or Omicron had nearly similar viral loads.
3. Scientists spot a blinking star’s ‘totally unexpected’ behaviour
The celestial object could be a slow spinning magnetar
Scientists have detected what appears to be an incredibly dense star behaving unlike anything else ever seen – and suspect it might be a type of exotic astrophysical object whose existence has been only hypothesised until now.
The object, spotted using the Murchison Widefield Array telescope in outback Western Australia, unleashed huge bursts of energy roughly three times per hour when viewed from Earth during two months in 2018, the researchers said.
First known example
It may be the first known example of what is called an ”ultra-long period magnetar,” they said. This is a variety of neutron star – the compact collapsed core of a massive star that exploded as a supernova – that is highly magnetised and rotates relatively slowly, as opposed to fast-spinning neutron star objects called pulsars that appear from Earth to be blinking on and off within milliseconds or seconds. The study is published in the journal Nature.
The object may be continuously beaming strong radio waves from its north and south poles. As that beam swept through the line of sight from Earth’s vantage point, it appeared to switch on every 18 minutes and 11 seconds for about 30 to 60 seconds, then off again. That is an effect similar to a lighthouse with a rotating light that seems to blink on and off from the perspective of a stationary observer.
It was found in a broader research effort mapping celestial sources of radio waves.
It is located relatively close to Earth in cosmic terms, roughly 4,200 light years away, where a light year is the distance light travels in a year, 9.5 trillion km.
Neutron stars including pulsars are among the universe’s densest objects. They are roughly 12 km in diameter – akin to the size of a city – but with more mass than our Sun. A neutron star with an extreme magnetic field, a magnetar, could potentially power the radio pulsations, the researchers said.
Slow with age?
As for why its rotation is so slow, it could be that it is very old and has slowed over time, according to Curtin ICRAR node astrophysicist and study co-author Gemma Anderson.
“This is more likely to be the ‘first of its kind’ rather than ‘one of a kind’,” Anderson said. The researchers have not detected it since 2018.“We are now monitoring this object using many different radio telescopes in the hope it switches ‘on’ again,” Anderson said.
4. Can a Russia-Ukraine conflict be averted?
Why does President Putin consider NATO admitting more members as a threat? What role are the U.S. and other countries playing to de-escalate the situation?
The story so far: Russia has mobilised some 1,00,000 troops on its border with Ukraine. Russia says the North Atlantic Treaty Organization’s eastward expansion (which the alliance calls “enlargement”) threatens its interests and has sought written security guarantees from the West. The crisis has unleashed a flurry of diplomatic moves with the U.S., NATO and the European Union holding talks with Russian officials.
What are Russia’s demands?
Russian President Vladimir Putin has demanded a ban on further expansion of NATO to include Ukraine, Georgia or other countries in Russia’s neighbourhood. Since the German unification in 1990, NATO has added new members five times. If the alliance had 12 founding members in 1949, it now has 30 members, including the three Baltic countries of Estonia, Latvia and Lithuania — all sharing borders with Russia — and Hungary, Poland, Romania and Bulgaria, all members of the former Soviet-led Warsaw Pact.
Mr. Putin has also asked NATO to roll back its military deployments to the 1990s level and ban the deployment of intermediate range missiles in areas that would allow NATO to reach Russia. Further, Moscow has asked NATO to curb its military cooperation with Ukraine and other former Soviet republics. In other words, Mr. Putin wants not just a halt to NATO’s future expansion but also its roll-back from Russia’s rim land.
What is the U.S. response?
The U.S. has given a written response to the Kremlin, which hasn’t been released. But public remarks made by President Joe Biden, Secretary of State Antony Blinken and other top officials suggest that the U.S. has taken a mixed approach of diplomacy and economic deterrence. The U.S. has ruled out changing NATO’s “open door policy” — which means, at least in theory, NATO could induct more members. The U.S. also says it would continue to offer training and weapons to Ukraine. But Washington is open to discussing missile deployment in Eastern Europe and a mutual reduction in military exercises. Also, it is highly unlikely that Ukraine and Georgia, both fighting separatist conflicts, would be taken into NATO in the foreseeable future. The U.S. has ruled out sending troops to Ukraine or taking other direct military measures against Russia in the event of an invasion. But Washington has threatened to impose severe economic sanctions on Russia if it makes any military move.
What are Putin’s options?
Russia says it won’t attack Ukraine. But the situation on the ground remains tense. Russia has already annexed Crimea, the Black Sea peninsula that was part of Ukraine, through a referendum. Russia is also backing separatists in the self-declared Luhansk and Donetsk republics (Donbas) in eastern Ukraine. Besides, Moscow has mobilised troops on Ukraine’s eastern border with Russia and northern border with Belarus, southern border with Crimea and south-western border with Transnistria (Moldova). It’s not clear what Mr. Putin will do next. If he goes for a full-throttle invasion, Russian troops could make swift moves into Ukraine from three sides. Another theory is that Russia could annex Donbas and launch limited incursions, capturing more territories along the Sea of Azov, establishing a land bridge from its border to Crimea. Or, Russia could provide further military assistance to the rebels in Donbas to push the frontline further into Ukraine without triggering a major international response. The other option is to de-escalate, claiming a diplomatic victory which would be based on guarantees from the West or a revival of the Minsk process that seeks constitutional amendments in Ukraine, giving more autonomy to the Russia-backed rebels.
What is India’s position?
India broke its silence on Friday, calling for “a peaceful resolution of the situation through sustained diplomatic efforts for long-term peace and stability in the region and beyond”. This was the standard position India had taken during the Crimean crisis as well. But the decisions it took after the annexation of Crimea offer insights into the thinking of policy-makers in New Delhi on Ukraine. Immediately after the annexation, India abstained from a vote in the UN General Assembly on a resolution that sought to condemn Russia. In March 2014, Mr. Putin praised India’s “restraint and objectivity”. In December that year, Sergey Aksyonov, the head of the Crimean Republic, visited India as part of Mr. Putin’s delegation, which had triggered an unusual criticism of India by the then Ukrainian President, Petro Poroshenko. In November 2020, India voted against a Ukraine-sponsored resolution in the UN General Assembly that sought to condemn alleged human rights violations in Crimea. So while India’s position is largely rooted in neutrality, New Delhi has adapted itself to the post-2014 status quo on Ukraine.
Is war imminent?
Russia says the U.S.’s written response doesn’t address its core concerns, but sees room for more dialogue. Top Russian and American diplomats would meet again in two weeks. French President Emmanuel Macron held talks with Mr. Putin to revive the Minsk process, which would be followed up with more talks in the coming weeks. The continuing diplomatic activities suggest that a military conflict is not imminent. But it’s too early to say whether de-escalation is in the offing.